Rotary machine



Aug. 2g, i923.

F. EGERSDRFER ROTARY MACHINE Filed Sent. 10 1920 www@ 3 Sheets-Sheet 2 Aug. 29 1923. n 11,466,276

F. EGERSDORFER RRRRRRRRRRRR NE Patented Aug. 28, 1923.

FRITZ' EGEBSDRFEB, OF CHARLOTTENBUBG, GERMANY.

ROTARY anonimi.A

Application led September 10, 1920. Serial No., 409,504.

To all whom t may concern: j

Be it known that I, FRITZ EGERSDRFER,

a citizen of Germany, residing at Charlot-v tenburg, Germany, have invented certain new and useful.. Improvements in Rotary Machines; and I do hereby4 declare the following to he a full, clear, and exact description of the invention, such as will enable others skilled in the art' to which it appertains to make and use the same.

My invention relates to improvements in rotary machines, and more particularly in machines of that class in which one or more reciprocating pistons or lungers are provided within cylindrical clhambers provided lengthwise and eocentrically of the axis ot rotation of a rotary member, which pistons are reciprocated upon rotation of the rotary member by a relatively stationary cam disk disposed atan angle to the axis ot' rotation and in loose engagement with the said pistons. One of the objects of the improvements is to provide a machine which is simple in construction and which permits operation of the machine at high speeds; With this and other objects in view my invention consists in the matters to be described hereinafter and particularly pointed out in the appended claims.

For the purpose of explaining the invention several examples embodying the same have been shown in the accompanying drawings in which the same reference characters have been used to indicate corresponding parts. In said drawings- Fig. 1 is a longitudinal section of one embodiment of the invention,

Fig. 2 is a cross section taken on the line 2 -2 of Fig. 1 and seen in the direction of the arrow, v

Fig. 3 is a lon 'tudinal section showing a modification of t e invention,

Fig. 4 is a detail view partly in section l showing the oscillating member connecting the reciprocating pistons,

Fig. 5 is a longitudinal section showing a further modification of the invention,

Fig. 6' is a cross-section of Fig. 5 taken on the line 6 6,

Fig. 7 is a cross section taken on the line 7-7 of Fig. 5 and Fig. 8 is a sectional detail view showingv the arrangement of one of tliefiuid ducts and the cooperating by-passage. The plane of section through the casing as shown in Figure 8 is approximately that indicated by the dotted line marked with the character 8 in Figure 6.

The example illustrated in Figs. 1 and 2 is particularly designed to be used as a pump or compressor. But I wish it to be understood, that'my invention is not limitthat the improvements apply also to machines which operate as engines. As shown the pump consists of a cylindrical casing 1 enclosing a rotary member 3 made integral with a shaft 2 projecting through a suitable bearing 2. formed in the head of the casing 1. Eccentrically of the axis of rotation of the drum 3 and parallel to the said axis, cylindrical bores or pockets 4 are formed in the member within which plungers or p1stons 5 'have reciprocating movement. The head 7 of the casing 1 which is opposite to the bearing 2 is formed with a cam face 6, which is disposed at an-angle to the axis of rotation'of the drum 3 and en gages the rear ends of the plungers 5. Upon rotation of the drum 3 the plungers 5 slide on .the inclined cam face 6 of the head 7 and they are forced inwards during one half of the rotation of thesaid drum. In such cases in which the machine is used as a pump the cam face 6 is not adapted to retract the -plungers 5 from the cylinders.

led to the use of the machine as a pump, and

For this purpose special means are provided which consist of a rocker 9 which is mounted on a pivot bolt 8 supported in suitable bearings 8 made integral with the drum 3. '-Ihe rocker is formed at its ends with rounded heads 10 which .engage in slot-s 11 made in the ends of the plungers 5. Therefore when one of the plungers is forced inward `by sliding upward along the cam face 6, it retracts the--fplunger1which is mounted on the opposite side of the axis of rotation. So 'both plun ers kare always in loose engagement with t e cam face 6, and none of the pistons can get out of contact with the said cam face, even if the pump rotates at high speeds. It appears that no parts are provided in the machine which by inertia would exert an objectionable fore on one of the movable parts.

Within the head of the casing 1 inlet and outlet ports 12 and 13 are formed which communicate with the inlet and outlet passages 12 and 13, and with which upon rotationof the drum 3 the open ends14 of the bores et come alternately into register. By this construction the admission and the outlet of the fluid is controlled merely by the rotation of the drum 3 and no valves are necessary for this purpose.

In Figs. 3 and 4; I have shown an example which is adapted to be operated at high speeds and to supply large amounts of fluid. As shown the drum `3 is formed with four cylindrical chambers 4 and plungers 5 are formed at their outer ends with slots 11. Each of the said slots is yengaged by the rounded end 10 of an arm projectingfrom a disk 15. The disk with its radiating arms is star-shaped, as'shown in Fig. 4. The said.

star disk is connected by a universal joint with the rotary head 3. As shown the shaft 4 2 to which the said head is secured is formed with a spherical pivot 16 and the annular star disk 15 is formed with a spherical bearing surface having universal movement on the said pivot. The disk 15, it will be observed, is in this instance formed of two disk parts bolted together, and the socket is an equatorial zone of a sphere. The compound structure of the disk, here alluded to, is a provision to facilitate assembly. When the structure is assembled, shaft 2 and disk 15 are, it will be observed, articulated together in a universal joint complete in itself. The parts are relatively movable both by -turning and by tipping. There is no dependence on any other member of the assembly to make the joint complete and secure. Such a self-contained joint I find of particular value in a high-speed machine, and in the ensuing claims T define the joint having the characteristics here. dwelt upon, in the phrase, inherently complete universal joint.

When the drum 3 is made to rotate the plungers slide with their outer heads on the inclined cam face 6, whereby they are reciprocated within the cylindrical chambers 4. .nasmuch as the path described by the tips of the arms of the star disk is truly circular while the pathdescribed by the ends of the plungers when referred to the plane of the disk is somewhat elliptical, there is` inv the course of operation some slight relative movement, in radial direction with respect to the center of turning of the disk, between disk and plunger.' Such movement is pro vided for in the slot engagement of the parts. The pressure of the plungers on the star and of the star on the plungers is always in the direction of the axis of the plungers. Tn order to provide a large contacting surface between theends of the pistons 5 and the inclined cam face and yet permitthe oscillating movement of the plungers `and cam relatively one to the other T prefer to equip the plungers with shoes 17 which arel in spherical engagement with the plungers and are formed with broad-bearing faces engaging recaer@ the camy face. (See Fig. 3.) These spherical shoes have universal movement relatively to the plungers. Therefore their flat bearing faces are always in full bearing contact With vthe cam face throughout the rotation of the drum3, and the said shoes also follow p the slight elliptical path. of the plunger ends, the departure from a truly circular path being due to the inclined position of the cam.

Under normal conditions the Hat bearing f In case the is Provided peripherally betweenthe outer circumference of the disk 7 7, and a bearing block 20, and the anti-friction bearing 19 is provided rearwardly between the rear face of the disk 7 and an obliquely disposed surface of block 20. The bearing 1,8 takes up the lateral pressure on the disk 7 caused by the inclined position of the latter, while the bearing 19 takes up the actual pressure. In this construction the annular disk 7 is free to take part in the revolution of the plungers 5. and the movement of the shoes 17 relatively 'to the disk 7 is only so much as is necessary to permit the elliptical paths of the shoes on the disk. Therefore friction between'the shoes 17 land the disk 7 is reduced to a minimum.

ln the example shown in Fig. 3 the block 20 is formed with a spherical outer surf-ace and the head of the casing 1 which supports the block 20 is in the form of a hollow sphere. Therefore the block 20 can be set within the head 21 indifferent positions,

for varying the angularity of the cam face relatively to the axis of rotation. For setting the block 20 in di'erent positions a crank arm 20 is connected therewith.

The left hand head of the casing 1 is provided with 'inlet and outlet ducts 12 and 13, with which upon rotation of the member 3 the cylinders Il: arel alternately bronght in communication. `Conmnunication is through slots 12 and 13' which eX- tend circumferentially but which are discontinuous and separated one from the'other by intervening unslotted portions of the body ofthe casing head. The unslotted intervals between the ends of the circumferential slots must be wide enough eectively to cut off communication between one d uc't and one cylinder'before communication is opened between that cylinder and the other duct. en the open endl of av cylinder 4 is traversing one of these inter.- mediate areas between the ends ofthe cirracaa'ze cumterential slots, the piston within the cylinder being in progress longitudinally of the c linder (say in direction from right to le t,.'Fig. 3),r considerable pressure Ywill. (unless provision is made to prevent) be roduced within the cylinders 4, because the uid which is being compressed by the movement of the plungers cannot ilow to the pressure duct 13. By reason of the high pressure, a part of the fluid is then forced between the head of the casing 1 and the member 3 and into the suction duct 12, so that the proper operation of the pump is interfered with. Furthermore the preure of the plungers on the cam face 6 is in this position of the plungers too high. An important feature of my invention consists in providing means whereby such high pressures and suchescape of liquid under pressure from the pressure side to the suction side are avoided.

With this object in view l'. provide bypassages by means of which the pockets 4 are brought into pressure-relieving communication with' the pressure duct 13 while they are moving over the intermediate areas of the casing head which separate the circumferential slots. l

Such by-passages are referably provided in both the examples s own in F1 s. 1 to 4. For the purpose of illustration prefer to show the said by-passages in separate views. For explaining this part of my invention I have shown in Figs. 5 to 8 `a pump of simple construction which is equipped with two plun a relatively fixed cam 6. e plungers bear with their free ends directly) on thel said cam and they are connected y a rocker 9, the construction of which is 'similar to that of the rocker 9 Shown in Figs.' 1 and 2.

In the ensuing description I shall follow the minute construction shown in Figs. 5-8, and which diers in detail somewhat from that of Figs. 1-4. The diierences however will be found to be mere matters of structurevariations the knowledge and skill of the engineer.

The inner ends 4out the pockets 4, 4 are made continuous with radial ducts 22, 23 which extend from the said pockets to the outer circumference of the 3. These ducts are adapted upon rotation-of thev drum 3 to be brought alternately into communication with the suction and pressure ducts 12 and 13. As appears from Fig. 6 the said ducts extending circumerentially of the casing arescparated from each other by unslotted portions 24, 25 of the casing wall. Vhen the drum 3 is rotated in the direction of the arrow shown in Figs. 6 and 'i' the plungers. 5. 5 move with their outer ends on the inclined cam 6 and they are forced during one half of their revolution into the cylindrical pockets 4 and they are rers 5 and 5 and tracted therefrom by means of the rocker 9 during the other half oft-he revolution. While the plungers perform their' suction strokes the ducts 22, 23 are in register' with 'the suction passage 12, and during the pressure stroke they are in register with the pressure passage 13. When the ducts 22 and 23 move over the wall surfaces 24 and 25 disturbances of pressure tend to be produced within the cylinders because the ducts 22 and 23 are closed from the suction and pressure passages and liquid can neither enter into nor escape from the pockets 4 and 4. Within that pocket whose plunger is beginning its suction stroke a tendency to vacuum is produced, and within the pocket whose plunger is beginning its pressure stroke a tendency to an increase of .pressure is produced. The latter particularly can if no preventive expedient' be provided be very high and objectionable.

To avoid such pressure disturbances 'l provide by-passages 26 and 27 which in the example shown in .the vfigures are formed within the drum and which are disposed in such a way, that they establish communication between the pockets 4 and 4 with the pressure passage 13, while the ducts 22 and 23 are closed by the wall portions 24and If. the pump be in the position shown in Figs. 5 and 6, the plunger 5 being withdrawn to its full extent from the pocket'4, and the plunger 5' being at the end of its inward stroke, further rotation of the drum 3 will ca the plunger 5 to the left as shown in Fig. 6, and atthe same time to the right as shown in Fig. 5. The fluid within the chamber 4 will then be subject to pressure.

But

at, this point the by-passage 26 comes into communication with ahy-passage 28 provided in the wall of the casing 1 and connected with the pressure passage 13, as is best shown in Fig. 8. Thus the bore 4 is brought into communication with the pressure passage 13. By reason of the circum-I ferential extent ofthe groove 24 this connection is maintained, until the duct 22 attains the pressure passage 13. During this part of the rotation of the drum3 the plunger 5 er'forms the first part of its pressure stroke and, though the duct 22 is closed by the wall 24, the liquid is free to escape through the by-passa-ge 26 to the pressure passae V13, so that excessive pressures are avoided? As the drum 3 is further rotated the duct 22 comes into full communicationwith the pressure passa-ge 13, so that the compressed liquid can tlow directly into the said passage. T-Vhen the duct 22 moves so far that it is covered by the wall 25, the by-passage 26 comes into communication with by-passage 29 provided in tbc lower part of the wall of the casing 1 and opening into the pressure passage 13. Upon furtherrotation of the `drum 3 the plunger 5 performs the last part los lll)

of its pressure stroke, while the duct 23 is closed from the pressure passage and connection between the pocket 4 and the pressure passage is maintained through the by\ passages 26 and 29, until the piston comes into the position which in Fig. 6 the piston 5 occupies. i At this point duct .Q2-opens to suction passage 12' and the piston 5 begins its suction stroke. Ilungcr 5 performs in duplicate the same operation.

In Figs. 6-8 I have shown. an example, in which for avoiding excessive pressures the cylindrical pockets l and 4 are connected by the by-passages with the pressure side of the pump, and I prefer this construction (because thereby any loss of compressed fluid is avoided), as compared to the construction in which the by-passages are so arranged as to connect the bores l and l with the suction side of the pump, (because in such a construction a part of the compressed fluid'would flow back into the suction passage.) Though the amount of fluid so wasted would be very small, I generally prefer the construction shown in the figures, and particularly so in cases inwhich the pump is designed for high pressures and high efficiency. But I wish it to be understood that my invention is not in this respect limited to the particular arrangement described herein and shown in the drawings.'

While in describing the invention reference has been made to various embodiments of the same, Iwish it to be understood that my invention is not limited to the particular constructions shown in the drawings. More particularly, I wish it to be understood that the construction of the by-passages has been illustrated in a pump provided with two plungers merely because in such a pump` the mvention can best be explained. But I wish it to be understood that-such by-passages may also be provided in constructions in which more than two plungers are 'employed-such for example as shown in Figs. 3 and 4.

I claim herein as my invention:

l. In a rotary machine, a cylindrical drum, and av cam member provided with a surface extending opposite and oblique to one head of said-drum, and means for imparting to one of said members rotation relative to the other on the axis of the drum, the said drum being provided with a plurality of bores, their axes parallel with the axis of the drum and the axis of one lying outside of a plane common to the axis of the other and to the axis of the drum, pistons within said bores adapted, to reciprocate in said bores and adapted to-bear upon the said obliquely disposed surface of said cam, and a rocker fulycrumed to said drum, and engaging said plungers, the fulcrum joint including a ball integral with the drum and a plurality of rocker parts adapted to be secured together and presenting when secured together a bearing surface in shape the equatorial zone of a sphere, substantially as described.

2. In a rotary machine, a cylindrical drum, a cam member provided with a plane surface extending opposite and oblique to one head of said drum, and means for'imparting toone of said members rotation relative to the other on the axis of the drum, said drum being provided with a plurality of bores remote from but extending parallel with its own axis, a plurality of plane-faced shoes adapted to slide upon the surface of said cam and provided each on its opposite side with a spherical bearing surface, a plunger in each of said bores provided with a speriL cal bearing surface adapted to vengage one of said shoes by the spherical bearing surface aforesaid, the said shoes in the operation of the machine being freely movable upon said cam surface radially with respect to the axis of rotation, according as the distance measured on the cam surface from the plunger end to the center of rotation varies.

3. In a rotary pump, the combination, with a cylmder member, a cam member, and

sure and suction ducts adapted to be alternately brought in communication with at least one of said cylinders.

4. In a rotary pump, the combination,-

with a cylinder member, a cylindrical casing enclosing the same and having-suction and pressure ducts which when the parts are assembled are separated from each other by intervening portions of the substance of the casing, a cam member, and means to impart relative rotary movement to said members, of a cylinder formed in said cylinder member eccentrically of the axis of rotary movement but extending parallel with said axis, a piston reciprocable in said cylinder and when the rotation of parts above noted is in progress reciprocated while in engagement with said cam member, said cylinders being adapted to be alternately brought in communication with'said pressure and suction ducts, and a by-passage adapted to establish connection between the cylinder and one of said ducts while the cylinder is moving over theHduct-separating portions of the casing wa 5. In a rotary pump, the combination, with a cylinder member, a cylindrical casing enclosing the'same and having suction and pressure ducts which when the parts are as-4 sembled are separated from each other by intervening portions of the substance of the casing, a cam member non-rotatable relatively to said casing, and means to impart relative rotary movement to said members,l

of a cylinderformed in said cylinder member eccentrically of the axis of rotary movement extending parallel with the said axis, such cylinder belng provided with a piston in engagement with saidvcam member for -and one of said ducts while the cylinder is moving over the duet-separating portions of the casing wall and while the plunger is performing its pressure stroke.

In testimony whereof I hereunto aiiix my signature.

FRITZ EGERSDRFER. 

